Process for repairing the tubes of a steam generator

Abstract

For repairing the tubes (2') of a steam generator (1), an impervious metallic sleeve is formed along the defective area (26) of the internal wall of a tube (2') by a wet process. The surface treatment is carried out on the spot in the tube (2') by means of a nickel solution free from chlorine, preferably a nickel sulphamate solution free from chlorine.

We claim: 
     
       1. A process for repairing the tubes (2) of steam generators by supplying an impervious internal metallic sleeve for covering a defective area, characterised in forming said sleeve by electrolytically depositing nickel from a nickel sulphamate soulution free from chlorine along the defective area (26) of the internal wall of the tube (2'), said depositing step including providing a closed cavity by sealing the front part (26) of the tube (2') along a length of from 20 to 80 cm in the manner of an electrolytic cell. 
     
     
       2. A process according to claim 1, characterised in providing an electrolytic cell having a consumable nickel or nickel alloy anode (12) immersed in the nickel sulphamate solution and held in the tube to be treated (2') by two plugs of synthetic material (17) elastically inserted into two neighboring tubes. 
     
     
       3. A process according to claim 1, characterised in providing at the upper part of the electrolytic cell a capillary orifice (10) through which the gases released during the process can escape.